If y=−m2, which of the following must be true? I) y is

varun289 wrote:If y=−m2, which of the following must be true?

I) y is negative.

II) m is non-negative.

III) If m is negative then y is negative.

Hey Varun,

y=−m2 can be interpreted in many ways.
You may need to add some brackets in order to remove the ambiguity from this question.

Presumably the 2 is meant to be an exponent.
But y=−m2 could still mean y = (-m)² or y = -(m²)
Which is it?

Cheers,
Brent

Also, what are the 5 answer choices?

Cheers,
Brent

Hi varun289,

Assuming that Mitch's version of the question is the version that you were looking at, then his explanation is correct (and it's exactly how I would have solved it).

As you continue to study, it's important in these types of questions to consider ALL of the possibilities that the question allows. Since there are NO restrictions in this prompt, then m COULD BE...

positive
negative
zero
integer
fraction

This prompt is more a test of your thoroughness than your math skills, so make sure that you are thorough with your work.

GMAT assassins aren't born, they're made,
Rich